A modern programming language that makes developers happier.

kotlinlang

what happens if you add the maven compiler plugin alongside the kotlin-maven-plugin ?

            &lt;plugin&gt;
                &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
                &lt;artifactId&gt;maven-compiler-plugin&lt;/artifactId&gt;
                &lt;version&gt;2.5.1&lt;/version&gt;
                &lt;configuration&gt;
                    &lt;source&gt;${java.version}&lt;/source&gt;
                    &lt;target&gt;${java.version}&lt;/target&gt;
                    &lt;encoding&gt;${project.build.sourceEncoding}&lt;/encoding&gt;
                &lt;/configuration&gt;
            &lt;/plugin&gt;

Mine seems to stick to Java8 probably because of the maven compiler plugin